Refactor organization of scope aware request utils

Reorganized the structure of the Request Utils due to their widespread use
resulting in circular imports issues (mostly because of middleware & logger).

pkg/requests/util/util.go

@@ -0,0 +1,48 @@
+package util
+
+import (
+	"net/http"
+
+	middlewareapi "github.com/oauth2-proxy/oauth2-proxy/v7/pkg/apis/middleware"
+)
+
+// GetRequestProto returns the request scheme or X-Forwarded-Proto if present
+// and the request is proxied.
+func GetRequestProto(req *http.Request) string {
+	proto := req.Header.Get("X-Forwarded-Proto")
+	if !IsProxied(req) || proto == "" {
+		proto = req.URL.Scheme
+	}
+	return proto
+}
+
+// GetRequestHost returns the request host header or X-Forwarded-Host if
+// present and the request is proxied.
+func GetRequestHost(req *http.Request) string {
+	host := req.Header.Get("X-Forwarded-Host")
+	if !IsProxied(req) || host == "" {
+		host = req.Host
+	}
+	return host
+}
+
+// GetRequestURI return the request URI or X-Forwarded-Uri if present and the
+// request is proxied.
+func GetRequestURI(req *http.Request) string {
+	uri := req.Header.Get("X-Forwarded-Uri")
+	if !IsProxied(req) || uri == "" {
+		// Use RequestURI to preserve ?query
+		uri = req.URL.RequestURI()
+	}
+	return uri
+}
+
+// IsProxied determines if a request was from a proxy based on the RequestScope
+// ReverseProxy tracker.
+func IsProxied(req *http.Request) bool {
+	scope := middlewareapi.GetRequestScope(req)
+	if scope == nil {
+		return false
+	}
+	return scope.ReverseProxy
+}